Anybody else that has an onboard computer which shows the instant consumption, I need to compare how mine is behaving.

When you are not moving, the display should show "---". Then as you start moving away, the display will show the litres/100km (or maybe mpg for all of you in the uk ) that you are using at that moment.

Now if I remember correctly, if you are coasting down a hill and you remove your foot from the accelerator, the Instant Consumption should slowly reduce the litres/100km until it gets to about 2 litres/100km, and then it either stays on 2 litres/100km or just shows "---" until you accelerate again.

The reason I am asking is because when I take my foot off the accelerator, my instant consumption rapidly rises until it says 50 litres/100km, and then when I accelerate, it decreases again to the correct value. Someone I spoke to said thats normal, but I somehow doubt it.

Sounds normal to me I don't have it on my Punto but for other cars that have that they do the same. If you're going downhill and using hardly any gas (remember it's still ticking over) then the mpg goes through the roof because you're doing a liot of miles without using much petrol. Then when you accelerate it takes a beating. Really it's nonsense there's not much you can tell from that so the one to look at is the average figure which works it out over the last 50miles or so.

I know what you are saying, except I think that my onboard computer is confused, because it is showing litres/100km and it is behaving like it is showing miles/gallon.

It used to work right, and inbetween someone set it to mpg, and then I set it back to l/100km, and it hasn't been right since.

Remember that for litres/100km, if you're not accelerating, then you're using 0 litres, and then when you accelerate, the number goes up, not down like with mpg.

The thing is, i am sure its also throwing out my average consumption figures, because the whole time it sits on 50l/100km when I am not accelerating, it is adding that value to calculate my average consumption.

Oh I see what you mean - well then I guess the only way to find out if it's wrong is work it out manually then check if it matches the computer for the average figure... I know that mine is always spot on so if yours is different the computer is definately wrong! Good luck anyway.

dint know you could get instant read fule usage readouts. my ful computer on my sporting shows you the average fule consumption since you set the trip computer and not what you are getting at the moment

Same as what mine does. I assume you can get an instant readout on more expensive models? No loss in any case because it's useless really it doesn't actually mean anything!

Instant MPG readouts are on the Mk 2.5 Punto's

I have an instant MPG readout on my trip computer, as well as an average. When I take my foot off the accelerater it shoots up sometimes into the high 100's. It's a great way of conserving fuel as you can adjust your driving to what the readout is.

Not sure about the litres/100km thing as we work on Miles in the uk.

Think mine has an instant readout - but I don't look at it cos it depresses me!

Found the answer

Somebody else was playing with my settings and set it to km/litre, instead of litres/100km, which is what its normally set on, and I didn't notice it was the wrong way round.

So that's why when I took my foot off the accelerator it went up, like miles/gallon does.